Matthew Zarrella and his dogs have traveled the world, finding missing people and solving mysteries for the U.S. military, the Peace Corps and the DEA.

The former Marine has been training search and rescue dogs for more than 20 years, and his 130-pound Swiss mountain dog, Hannibal, became the state’s first K-9 officer.

Zarrella's dogs have conducted searches for the state, as well as for the Defense Department, the FBI, the Peace Corps and the U.S. military.

They helped find a mass grave in Colombia for the DEA, and they solved a 40-year-old mystery when they found the remains of a U.S. pilot shot down in 1965.

"Bone fragments the size of your fingernail," Zarrella told NBC News, describing the scene in Vietnam. "Just an amazing accomplishment by the dogs."

Although Zarrella praises his dogs for their finds, his colleagues say he deserves his share of the credit. Many say he seems to have a supernatural connection with his dogs, including Max, a German shepherd Zarrella adopted and trained a decade ago.

"Matt Zarrella is the best there is," K-9 unit member James Rawley told The Christian Science Monitor. "He and Max are so tuned in to each other. Matt's able to read his dog before anyone else in the room even knows what's going on."

Zarrella rescued Max from the pound when he was 6 months old.

"He was a handful, spinning around and barking. But I could tell he had excellent problem-solving ability," he said.

Zarrella gets all his canine recruits from animal shelters and has saved many of them from euthanasia. One of his newest dogs, a 2-year-old Australian shepherd/border collie mix named Ruby, was just hours away from being put down when he found her.

"I wanted to take a dog that didn’t have a shot, that I know physiologically can do the work. It's just a matter of motivation," he said.